Far-Left “anti-fascists” (antifa) have injured at least two police officers and torched a squad car in Cologne, Germany, after attempts to shut down a party convention for the anti-mass immigration Alternative for Germany (AfD) led to clashes with the authorities.

The demonstrators, many in all-black, identity-concealing Blac Bloc attire, tried to prevent roughly 600 party delegates from entering their hotel venue, requiring police to escort them through the security perimeter. The Guardian newspaper reports that one officer sustained a “facial injury” while doing so, leading to an arrest.

Up to 4,000 police, many in riot gear or mounted on horseback, were deployed to control an estimated 50,000 demonstrators, including roughly a thousand Far-Left agitators.

A police spokesman described the atmosphere as “very dynamic” and “fairly aggressive” in places. Footage broadcast by the n-dtv network showed antifa marching under the cover of smoke bombs, throwing lit flares and trying to frighten police horses.

Thirteen wedding couples in the city had to be escorted by police for their own safety, with one bride telling reporters, “We’re getting straight out and celebrating in Bochum [another city in the region].”